In the mid-1960s Nevo started a long-term project in animal communication underlying speciation and adaptation (vocalization, olfaction, and vibration) in mole crickets, toads, frogs, and mole rats (Spalax). Another behavioral program begun in the mid-1970s involved
the genetic evolution of aggression and pacifism in Spalax. This program culminated in a verbal model of aggression evolution predicting and then leading to the discovery of a totally pacifistic mole rat species at the northern margin of the Sahara Desert. This species originated from Israeli polymorphic populations of mole rats involving behavioral phenotypes for aggression with militant, intermediate, and pacifist types. Currently, efforts are being made to sequence and clone aggression genes from Spalax genetic libraries and to sequence them in
an attempt to unravel the molecular genetic basis of aggression in mole rats. Another behavioral project initiated by Nevo is devoted to facial expressions of human emotions. Together with his students and collaborators, he showed the existence of a strong hereditary basis for this important component of human communications.
